This invention relates to a rotary vise structure of versatile application, which can be used to advantage for holding an article while work is performed on the article, and which provides a facility for selectively rotating the article to different rotational positions while it is clamped in the vise. Among the diverse uses of a vise structure in accordance with the invention, for example, is its suitability for holding a small IC engine of the type commonly used on lawnmowers and the like, while servicing and/or testing the engine.